Three sex offenders in Northern Ireland are at large, the PSNI confirmed.

The whereabouts of three registered sex offenders is currently unknown, but it is not known how long they have been missing.

The information came to light following a Freedom of Information request by the Press Association.

Following their request, the PSNI said three sex offenders were "currently wanted" but did not reveal when the offenders went missing.

The force said it refused to disclose the names of those missing as the information may be "valuable" for "criminal/ terrorist/ vigilante groups who may attempt an attack on them and/or their families".

Registered sex offenders - including rapists and paedophiles - are required to inform police and probation officers of their addresses and are supposed to be monitored by officials working under multi-agency public protection arrangements (MAPPA).

But in FOI responses to the Press Association, 39 forces revealed there were missing registered sex offenders in their areas in February or early March.

The figures have shown 396 registered sex offenders are wanted because their whereabouts are unknown, including some who have been missing for more than a decade. One convicted sex offender in Gloucestershire has been missing since the year 2000, another in Northumbria disappeared in May 2002.

All forces stressed the figures could change as arrests are made or new cases come to light.

Every force to respond to the Press Association refused to name those missing over concerns of vigilante attacks or because the information was exempt under data protection laws.

The Metropolitan Police, the UK's largest force, said 167 registered sex offenders were wanted in London alone, including one offender who had been missing for 14 years.

The NSPCC described the figures as "alarming" and said its own research had found there was just one police staff member responsible for every 50 registered sex offenders.

Jon Brown, the charity's lead for tackling sexual abuse, said: "About half of those on the register are offenders who have raped or sexually assaulted children, or committed online child abuse image offences, however most just receive one police visit a year after they have been released from prison and a period of supervision.

"The monitoring of registered sex offenders in communities needs urgent attention by the Government to ensure it is fit for purpose."

The NSPCC said there were around 900 police officers and non-uniformed staff responsible for managing more than 46,000 registered sex offenders.

Deputy Chief Constable Michelle Skeer, who is the National Policing Lead for the Management of Sexual Offenders and Violent Offenders, said: "A large proportion of the recorded wanted or missing sex offenders are, following investigation, either known or believed to be living abroad or have returned to their country of origin. When registered sexual offenders (RSO's) are missing or wanted in the UK, all police forces are alerted. If they return to the UK, there are several processes in place to ensure that they are brought to the attention of police and arrested where appropriate."